3-Quinolinecarboxamide derivatives are described in U.S. Pat. Nos. 4,547,511, 6,077,851, 6,133,285 and 6,121,287. The term “3-quinolinecarboxamide derivative” as used in this specification designates the undissociated acid form, hereinafter called the neutral form, of the compound of formula (I), i.e., the form as given in the formula (I).

It was unexpectedly found that some 3-quinolinecarboxamide derivatives in the neutral form disclosed in the above US patents are susceptible to chemical degradation in solid state, and, in particular, when in pharmaceutical formulations. Some salts of the 3-quinoline-carboxamide derivatives of formula (I) are known from said US patents. However, none of the above-mentioned patent specifications discloses an enabling method of providing 3-quinoline-carboxamide derivatives of formula (I) susceptible to degradation in a sufficiently stable pharmaceutical form or even suggests any particular advantage of using the salt form of a 3-quinolinecarboxamide derivative in pharmaceutical formulations.
There are two types of solids, i.e., crystalline and amorphous. They have differences that are very important in physical pharmacy. Crystalline solids are arranged in fixed geometric patterns or lattices, and show a definite melting point. Amorphous solids can be considered supercooled liquids in which the molecules are arranged in a random manner, somewhat as in the liquid state, and do not have definite melting points. The formation of either an amorphous or a crystalline form of a 3-quinolinecarboxamide salt wherein n is an integer of 2 or 3 is influenced by the conditions under which the salt is obtained, and the forms can be distinguished in a laboratory by X-ray powder diffraction spectroscopy.
The solid state physical property of a pharmaceutical compound is important to its dissolution, which may have stability consequences. Solid state physical properties also affect the way a pharmaceutical compound should be handled during processing into a pharmaceutical product such as a tablet or capsule formulation, e.g., physical properties can impact the type of excipients to add to a pharmaceutical formulation.